Network devices maintain configuration information that defines operation of the network devices. For example, network devices such as routers, switches and gateways maintain tables of routing information that describe routes through the network. Most routers include a control plane, sometimes called a management plane, which maintains the routing information, and a forwarding plane, which forwards received packets according to the routing information. Upon receiving an incoming data packet, the router examines destination information within the packet to identify the destination for the packet. Based on the destination, the device forwards the packet in accordance with a routing table. In the same manner, network devices such as firewalls maintain rules that define the devices and services permitted to cross the firewall.
Network services may be distributed across multiple devices. Some of these services are connectivity services, such as a layer three Virtual Private Network (“L3 VPN”) service, a Virtual Private Local Area Network (LAN) Service (“VPLS”) and a point to point (“P2P”) service, and some are network configuration services, such as “dot1q vlan service.”
Network administrators use a network management system (NMS) to discover, monitor and configure devices present on the network. In addition, network administrators use some network management systems to define “custom services” on the fly and to configure the appropriate devices to instantiate the service. The network management system then manages the complete life cycle of each service defined in the NMS.